Galectins are beta-galactoside-binding lectins that play multiple roles during tumor progression. Previous work conducted in our laboratory has demonstrated decreased galectin-3 expression in carcinomas from colon, breast, ovary and endometrium, compared to the corresponding normal tissues. In this study, we examined the pattern of galectin-3 expression by immunohistochemistry in a group of 10 basal cell carcinomas of the skin. In the surrounding normal skin, galectin-3 immunostaining was found predominantly in the middle epidermis (spine layer) and eccrine sweat glands. Compared to the normal epidermal cells, basal carcinoma cells observed in all 10 samples examined presented with significantly decreased galectin-3 immunostaining. These data further demonstrates that galectin-3 is down-regulated in a variety of human cancers, including basal cell carcinoma. [less ▲]

Tumor cell adhesion and migration to laminin are important events during invasion and metastatic spread. Galectin-3, a multifunctional member of the galectin family, binds specifically the poly-N ... [more ▼]

Tumor cell adhesion and migration to laminin are important events during invasion and metastatic spread. Galectin-3, a multifunctional member of the galectin family, binds specifically the poly-N-acetyllactosamine residues of laminin and has been implicated in tumor invasion and metastasis. Galectin-3 is multimerized by transglutaminase, an enzyme that catalyzes cross-linking between glutamine and other aminoacid residues. In this study, we examined the consequences of transglutaminase-mediated galectin-3 oligomerization on the interactions between cancer cells and laminin. We first demonstrated that human galectin-3 is cross-linked by guinea pig liver transglutaminase, forms oligomers, and incorporates the marker 5-(biotinamido) pentylamine. Expression of transglutaminase activity in the A375 and A2058 human melanoma cell extracts was revealed by its ability to induce galectin-3 oligomerization and 5-(biotinamido) pentylamine incorporation. Transglutaminase-treated galectin-3 did not affect adhesion or migration of the melanoma cells to laminin but consistently induced a significant increase of the percentage of cell spreading compared to the control (23.5 +/- 2.3%, vs. 10.6 +/- 1.9% at 180 min, p < 0.05), or to untreated galectin-3 or transglutaminase alone. Our study is the first demonstration that human galectin-3 is oligomerized by transglutaminase with, as a consequence, a specific effect of melanoma cell spreading on laminin. This phenomenon could be of significance in the modulation of cancer cell interactions with laminin during tumor invasion and metastasis. [less ▲]

Interactions of cancer cells with laminin play a critical role during the progression of solid malignant tumours. Increased expression of the 67 kD laminin receptor (67LR), one of the several laminin ... [more ▼]

Interactions of cancer cells with laminin play a critical role during the progression of solid malignant tumours. Increased expression of the 67 kD laminin receptor (67LR), one of the several laminin binding proteins, is associated with the invasive and metastatic capacity of various types of cancer, including breast, colon, ovary, lung, and endometrial carcinoma. In this study, 67LR expression was analysed in a series of cervical biopsy specimens including 16 normal cervical tissues, 36 low-grade squamous intraepithelial lesions (SILs), 24 high-grade SILs, and 11 invasive carcinomas. Detection of the 67LR was performed using immunoperoxidase staining and the monoclonal antibody MLuC5 which specifically recognizes the 67LR. Immunostaining of the 67LR was correlated with human papillomavirus (HPV) type detected by in situ hybridization and with proliferative activity of the lesion determined by immunohistochemistry with the MIB-1 monoclonal antibody, specific for the Ki67 antigen. Increased expression of the 67LR was correlated with the histological severity of the lesions, with the strongest immunoreactivity being found in invasive carcinomas. Significant differences in 67LR expression were found between normal cervical epithelium and high-grade SILs (P < 0.05, non-parametric Mann-Whitney test) or invasive carcinomas (P < 0.001), as well as between low- or high-grade SILs and invasive carcinoma (P < 0.01 and P < 0.05, respectively). Ki67 antigen expression also increased with the severity of the lesions. There was a positive correlation for each type of lesion between expression of the 67LR and of the Ki67 antigen. No specific relationship was found between 67LR or Ki67 antigen immunostaining and HPV type detected in SILs, segregated into low-grade and high-grade lesions. These data add weight to the evidence that increased expression of the 67LR is a consistent, but not sufficient feature of the invasive and metastatic phenotype and suggest that high expression of the 67LR might be associated with both more proliferative and more aggressive cervical (pre)neoplastic lesions. [less ▲]

Human placentation is a complex biological phenomenon that results from precisely regulated interactions between cells and the extracellular matrix. Galectin- 1 and galectin-3 belong to a newly defined ... [more ▼]

Human placentation is a complex biological phenomenon that results from precisely regulated interactions between cells and the extracellular matrix. Galectin- 1 and galectin-3 belong to a newly defined family of galactose-binding lectins that can bind several glycoconjugates such as the basement membrane glycoprotein laminin, and are involved in many biological events including cell adhesion. In this study, the expression of these two galectins in first and third trimester normal human placenta was examined using single and double immunohistochemical staining and specific antibodies for galectins and cytokeratins. Galectin-3 was detected in all trophoblastic lineages including villous cytotrophoblasts and extravillous trophoblasts (trophoblastic cell columns, infiltrating trophoblasts, endovascular trophoblasts and placental bed giant cells). On the contrary, galectin-1 distribution was restricted to endometrium. A reduction of galectin-3 expression was observed from the villous trophoblasts to the trophoblastic cell columns. This pattern correlated with the switch from a proliferative to a migratory phenotype. Galectin-1 and galectin-3 were both detected in maternal decidual cells. Our data demonstrate a specific pattern of galectin-1 and galectin-3 expression in trophoblastic tissue, and suggest these lectins could contribute to cell-cell and cell matrix interactions of trophoblast during placentation. [less ▲]

in Biochemical and Biophysical Research Communications (1995), 209(2), 760-7

Galectins constitute a gene family of beta-galactoside-specific lectins that show high homology in their carbohydrate-binding site. They have been postulated to be involved in many biological events, but ... [more ▼]

Galectins constitute a gene family of beta-galactoside-specific lectins that show high homology in their carbohydrate-binding site. They have been postulated to be involved in many biological events, but their specific functions are not yet well defined. Galectin-1 is a laminin binding protein that recognizes poly-N-acetyllactosamine chains on this major basement membrane glycoprotein. In this study, we analyzed the possibility that galectin-1 could modulate interactions between human melanoma cells and laminin. We demonstrated that A375 and A2058 cell lines express galectin-1 both intracellularly and on the cell surface. In an in vitro assay, recombinant galectin-1 increased melanoma cell attachment to laminin in a dose-dependent manner. This effect was abolished by lactose. Anti-galectin-1 inhibited adhesion of melanoma cells to laminin in a dose-dependent fashion. However, neither galectin-1 nor anti-galectin-1 antibody affected melanoma cell spreading on laminin in vitro. These data indicate that galectin-1 might participate in melanoma cell adhesion to laminin and therefore could be a modulator of invasion and metastasis. [less ▲]

Ovarian carcinomas constitute the major cause of the mortality and morbidity in gynaecology. Most ovary carcinomas are epithelial tumours. Our understanding of ovarian cancerogenesis has been hampered by ... [more ▼]

Ovarian carcinomas constitute the major cause of the mortality and morbidity in gynaecology. Most ovary carcinomas are epithelial tumours. Our understanding of ovarian cancerogenesis has been hampered by the lack of a well defined precursor lesion, the lack of knowledge about tumour progression, and by the relative inaccessibility of the ovaries in the abdominal cavity. Recent studies using experimental models allow us to better define the fundamental mechanisms of carcinogenesis from the serous ovarian cells and of invasion of the abdominopelvic cavity by proximity. This review article tries to update on epidemiology, genetic syndromes, biology, screening, and therapy of these epithelial tumours, and about the new directions taken by basic and clinical research. We will present data concerning oncogenes and tumour suppressor genes involved in epithelial ovarian tumours, regulation of tumour cells by growth factors, genes involved in tumour invasion, and mechanisms used by the cancer cell to resist to therapies. Non-epithelial ovarian tumours will not be examined in this manuscript. [less ▲]

Galectin-3 is a laminin binding protein which expression is altered in a variety of human carcinomas including colon, breast and endometrium. In these tumors, we consistently observed a down regulation of ... [more ▼]

Galectin-3 is a laminin binding protein which expression is altered in a variety of human carcinomas including colon, breast and endometrium. In these tumors, we consistently observed a down regulation of galectin-3 expression related to increased aggressiveness. Galectin-3 belongs to a family of galactose-binding lectins and binds laminin through its numerous poly-N-acetyllactosamine chains. To date, the exact role of galectin-3 in the complex interactions between cancer cells and laminin has not been clearly defined. Adhesion of melanoma cells to laminin is a critical event during tumor invasion and metastasis. In this study, we explore the possibility that galectin-3 could modulate attachment of two human melanoma cell lines to laminin. A2058 and A375 melanoma cell expressed galectin-3 on their surface as demonstrated by immunofluorescence, and attached to laminin in an in vitro assay. We demonstrate that neither recombinant galectin-3 nor an affinity purified antigalectin-3 antiserum altered adhesion of A2058 or A375 melanoma cells to laminin. Our data strongly suggest that galectin-3 is not a key element in adhesion of the melanoma cells to laminin. These results are not surprising in light of the observation that galectin-3 expression is down regulated in cancer and that increased adhesion to laminin is a constant feature of invasive cancer cells. [less ▲]

in Biochemical and Biophysical Research Communications (1994), 201(1), 388-93

Tumor invasion of host tissues and trophoblastic penetration of the endometrium share common biological features. Both processes involve the invasion of basement membranes, an event that is initiated by ... [more ▼]

Tumor invasion of host tissues and trophoblastic penetration of the endometrium share common biological features. Both processes involve the invasion of basement membranes, an event that is initiated by adhesion of cancer or trophoblast cells to basement membrane components and particularly to laminin. Adhesion to this latter glycoprotein is mediated through a variety of cell surface receptors. We have previously shown that the 67 kD Laminin Receptor (67LR) and a 31 kD Human Laminin Binding Protein, recently renamed galectin-3, are inversely modulated as the invasive phenotype of cancer cells progresses, with up regulation of the former, and down regulation of the latter, respectively. In this study, we examined the expression of these two proteins in 27 human trophoblastic specimens at different gestational ages using Northern and Western blot techniques. Expression of the 67LR increased from 7 weeks to a maximum at 12 weeks, when invasion is maximal, and then decreased. Expression of galectin-3 was inversely modulated by the gestational age, with a minimum expression at 12 weeks. Our data demonstrate that invasive trophoblast displays the same pattern of laminin binding proteins expression than invasive cancer cells, and further demonstrates that invasion of the extracellular matrix by trophoblast and cancer cells share common molecular mechanisms. [less ▲]

The expression of the 67-kD laminin receptor (67LR) and the 31-kD human laminin-binding protein (HLBP31), two proteins involved in cancer cell laminin interaction, was evaluated on 30 ovarian cancer specimens. Expression of the 67LR was increased (up to 2.5-fold, in 87% of the patients), while HLBP31 expression was downregulated in cancer cells compared with the normal tissue, as detected by northern blotting and immunohistochemistry. The immunohistochemical study demonstrated that the 67LR was significantly overexpressed (P < 0.05) in the group of patients whose cytoreductive surgery was suboptimal, and those with poor clinical outcome. No correlation was observed between HLBP31 expression and clinicopathological features. Increased expression of the 67LR appears to correlate with the invasive phenotype of ovarian cancer cells and suggests a role of the latter in ovarian cancer invasion. [less ▲]

in International Journal of Cancer = Journal International du Cancer (1992), 52(4), 653-7

Invasion of basement membranes by cancer cells is a critical step in metastasis, which requires the coordinated expression of specific genes such as laminin receptors and metalloproteinases. Estradiol and ... [more ▼]

Invasion of basement membranes by cancer cells is a critical step in metastasis, which requires the coordinated expression of specific genes such as laminin receptors and metalloproteinases. Estradiol and progesterone modulate the clinical progression of steroid-sensitive breast cancers; however, little is known about the molecular regulation of the invasive phenotype by these hormones. We therefore examined the effects of 10 nM estradiol and/or 10 nM progestin R5020 on the expression of 2 non-integrin laminin binding proteins, the 67-kDa laminin receptor (67LR) and HLBP31 as well as the 72-kDa type-IV collagenase (MMP-2) and its inhibitor, TIMP-2, in steroid-receptor-positive (T47D and MCF-7) and -negative (MDA-MB 231) human breast-cancer cells. The relative steady-state level of 67LR mRNA was increased 2- to 3-fold by estradiol in both MCF-7 (p < 0.001) and T47D (p < 0.001) cells, also by R5020, alone or in combination with estradiol, in T47D cells (p < 0.001) and to a much less extent in MCF-7 cells. HLBP31 mRNA and protein levels were increased 2- to 3-fold (p < 0.001) by R5020 alone or in combination with estradiol, but not by estradiol alone. None of the steroid treatments affected the expression or activity of MMP-2. Interestingly, however, TIMP-2 mRNA levels and protein expression in MCF-7 and T47D cells were 50% down-regulated (p < 0.001) by treatment with R5020 or R5020 plus estradiol, but not by treatment with estradiol alone. None of these genes were modulated in steroid-independent MDA-MB231 cells. The data suggest that estradiol and progesterone might act as coordinators regulating specific genes in the steroid-sensitive breast-cancer cell, leading to the acquisition of the metastatic phenotype. [less ▲]

BACKGROUND: Interactions between cells and the basement membrane glycoprotein laminin are altered during colon cancer progression. Colon carcinoma and normal mucosa cells express a variety of laminin-binding proteins, including the 67-kd laminin receptor (67 LR) and a 31-kd human laminin-binding protein (HLBP31) homologous to the 31-kd human IgE-binding protein/galactoside-binding lectin. PURPOSE: To investigate whether various laminin-binding proteins are differentially expressed in human colon carcinoma, we studied messenger RNA (mRNA) levels of the 67 LR and HLBP31 in matched tumor and adjacent normal mucosa samples from a series of 21 patients. METHODS: Total cellular RNA from tumor and normal mucosa was isolated and analyzed by Northern and slot blot hybridization. In addition, HLBP31 protein levels were assessed by the immunoblot technique. Quantitative laminin affinity chromatography was also used to measure the synthesis of HLBP31 protein in five human cancer cell lines. RESULTS: The steady-state mRNA level of HLBP31 was downregulated (i.e., decreased) in 18 of 21 human colon carcinomas compared with the level in their corresponding normal colonic mucosa. On average, the level of HLBP31 mRNA was decreased 50% +/- 30% (+/- SD) in the colon cancers. The mean ratio of colon cancer HLBP31 mRNA to adjacent normal mucosa HLBP31 mRNA was twofold lower in primary tumors of patients with metastases (0.3 +/- 0.2 SD) than in primary tumors of patients free of metastatic lesions (0.6 +/- 0.2 SD). The differences between the two groups of patients were statistically significant (P less than .05, Wilcoxon-Mann-Whitney test). We have previously shown that the ratio of colon cancer 67 LR mRNA to corresponding normal mucosa 67 LR mRNA was increased in the same patient population. When the two ratios (ratio of cancer to normal HLBP31 mRNA and ratio of cancer to normal 67 LR mRNA) were compared, HLBP31 mRNA/67 LR mRNA was significantly lower (P less than .05) in primary tumors with metastases (mean +/- SD, 0.3 +/- 0.2) than in primary cancers without metastases (mean +/- SD, 0.7 +/- 0.5). The steady-state level of HLBP31 mRNA was directly correlated with the amount of HLBP31 protein in both colon tissue samples and human cancer cell lines. CONCLUSION: HLBP31 mRNA expression in colon cancer tissues is modulated inversely to that of 67 LR mRNA expression. The down-regulation of HLBP31 appears to be associated with the metastatic capabilities of colon cancer cells. IMPLICATIONS: Prospective studies on a large cohort should determine if the systematic detection of HLBP31 and 67 LR protein and/or mRNA can be a valuable adjunct in the prognostic evaluation of primary colon cancers. [less ▲]